Posted
by
ScuttleMonkey
on Friday March 09, 2007 @01:02PM
from the straight-and-narrow dept.

Thomas Hawk writes "Last month Robert Scoble and I were able to do a video/photo shoot of the Stanford Linear Accelerator Center (SLAC) with SLAC Emeritus Bebo White. SLAC is both the longest and straightest building in the world and is the home of three Nobel Prizes in physics. There is also a video tour available; part one and part two."

That video was posted weeks ago! Somebody's been SLACing off, apparently. Though I will cut them some SLAC, since the videos are really quite interesting. That's a SLAC piece of equipment they have there at SLACford...

I can't remember Bebo's real name but he has been going by Bebo all his life. If memory serves correct, he got the name when he was a child. I think it was what his sister called him and it's the name that stuck with him his entire life. He really is a great guy and gave us a great view of SLAC. I'm looking forward to going back there to take photos and film part III with Robert and Shel.

I remember Bebo at the Computer Center quite well. I worked with him as an interested member of the SLAC user community. I helped him and his group concerning certain aspects the three mainframe IBM computers sort of lashed together. They called that the "Triplex".

It's all about radio-controlled tanks. It's a lot easier to get them unstuck without pulling them back towards you. You can typically pick up a decent model at radio shack. I like the crossbow idea, though.

I worked at SLAC for more than 6 years, night shift in the accelerator maintenance. It's not the rat droppings, it's the black widows you need to watch for. I once killed more than 20 of them -- and that was in one sector (100m), on one task (ranging). And that's only the ones that were in my way.

"Straightest building". Does this mean that the building is constructed to take into account the curvature of the earth? Granted this would only be less than half a meter (if I did the math right), but would seem to be important in this sensitive of a project.

Yes, the building itself does curve with the surface. I have been in it, and if you kneel down on one end you can see the earth's curve looking toward the other end (when there isn't something in the aisle on either side of the cyclotrons).

I'm no physicist, but I think in order to "be straight" it must follow the curve of earth's gravitational field. Not sure if I understand that correctly, but if physicists say that an orbit is a straight line through space/time (in a sense), then it follows that a straight line inside a planetary gravitational field would have a curve to it.

Not sure if I understand that correctly, but if physicists say that an
orbit is a straight line through space/time (in a sense), then it
follows that a straight line inside a planetary gravitational field
would have a curve to it.

The curve you are talking about is the path that a light beam
would follow, not the curvature of the earth. Otherwise, the earth
would look flat to someone on the surface, and of course it
doesn't, since ships, etc. disappear over the horizon.

Yes. The actual accelerator (like all currently built) is truly straight so the distance between the floor of the klystron gallery (the long building on the surface) and beam pipe beneath varies. As someone else mentioned the variation is negligible (from an engineering perspective).In contrast, the International Linear Collider, which will be tens of kilometres long, will curve to follow the surface of the earth, since it is long enough that it would create engineering problems to try and go in a straigh

That is the point about straightest building. They're accelerating electrons, so bremsstrahlung (= energy loss due to curves, grows very fast with decreasing particle mass, decreases slowly with the radius of curvature) is a real problem. In order to eliminate bremsstrahlung, the SLAC building doesn't follow the earth's curvature, but instead is straight in the same sense that a lightbeam is straigh.

I once calculated the amount of energy the LEP (CERN's old huge accelerator, a 20km approx. circle) lost due to bremsstrahlung. IIRC it amounted to one 100W lightbulb every 10cm or 20MW of enrergy loss, simply due to the curvature.

Currently a new huge linear accelerator is being discussed inside the scientific community. They want to use supraconducting magnets, which in terms requires large reservoirs of cooling liquids. Since liquids are subject to gravitation it may be that they will build it following the earth's curvature in order to keep the cooling circuits simpler. These issues haven't been decided yet.

I think SLAC actually does NOT follow the curvature of the earth. I remember touring it as a fifth grader and being rather amazed when they told us that you can get on rollerblades at one end & have gravity pull you (albeit very slowly) toward the middle.

Also, as one of the previous posters noted, if you have electrons going at relativistic speeds and you force them to curve to match the curvature of the earth, you're essentially going to be creating a sort of a syncrotron radiation source (SLAC does

The accelerator itself follows an exactly straight line, it traces a
chord [wikipedia.org]. The surface building, which is actually over the accelerator and contains the power systems and microwave generators, follows the curvature of the Earth.

When I visited the place I put my head on the floor and could see it curving out of view.

Yes, the accelerator really is straight in that sense. My back of the envelope calculation says it's about 20 cm deeper in the center than at the start and end. I'm not really sure if the floor of the building is that straight, though, and it doesn't really have to be - it would be really hard to make that happen in a single pour of concrete (according to my info they did in fact pour the entire 2 miles in a single pour, hundreds of cement trucks were lined up). The accelerator is mounted on a "strongback"

No, those physicists sound completely legitimate. On the other hand, Bebo sounds like a little furry pokemon thing or some sort of cute anime character. Well, except Zoltan. That guy sounds like he's either a Transformer or he's trying to generate massive earth-based black-holes so he can hold the planet ransom for one million dollars.Also, your average scientifically-interested slashdotter apparently things that a refrigerator modified to catapult you a can of beer is awe-inspiring and amazing. I don't put

I visited RIKEN's accelerator in Wako City, Saitama Prefecture, Japan last year and was told they were one of only three facilities in the world manufacturing proton beams for medical purposes. The other two were in Germany and at Stanford, but I was told that Stanford had closed its facility so now there are only two.

Perhaps antimatter is better than proton beam, I don't know. Sounded like it is extremely expensive to run.. anybody know? I saw how RIKEN uses CAD to design thick IIRC bronze beam masks. It is underground and the whole building is built like a ship apparently, separate from the surrounding earth, which presumably helps it stably ride out earthquakes. They opened in Dec. 2006 the most powerful radioisotope accelerator, accelerating aluminum to 70% c.

I am not a physicist nor do I work there but am curious about these aspects concerning the place mentioned in the article.

I visited RIKEN's accelerator in Wako City, Saitama Prefecture, Japan last year and was told they were one of only three facilities in the world manufacturing proton beams for medical purposes. The other two were in Germany and at Stanford, but I was told that Stanford had closed its facility so now there are only two.

You are confused. SLAC != Stanford. SLAC is operated by Stanford under an agreement with the DoE. The accelerator at SLAC does not provide proton beams. It has been a electron-positron mac

I see, thanks. I was told this info by the Japanese at RIKEN, that Stanford had closed a similar facility. And that Japan could only afford it because it was on the political agenda. I remember a 300 million dollar number but don't know if that is yearly or what it cost to build.I meant better for anticancer. TFA states 4 times better IIRC.

As for elephants, a RIKEN page in which it collaborates with another lab (I don't remember if it is Brookhaven or what) calls itself experiements with particles that weig

I see, thanks. I was told this info by the Japanese at RIKEN, that Stanford had closed a similar facility. And that Japan could only afford it because it was on the political agenda. I remember a 300 million dollar number but don't know if that is yearly or what it cost to build.

Stanford might have had a similar facility, but that facility is not SLAC.

As for elephants, a RIKEN page in which it collaborates with another lab (I don't remember if it is Brookhaven or what) calls itself experiements with part

There was a proton facility at Loma Linda Medical Center when I was there a few years ago. Not sure what you meant by manufacturing proton beams. Maybe those places you mentioned made the equipment used at LLMC.

SLAC is kind enough to allow the Foothiils Amateur Radio Society to hold a monthly outdoor/indoor amateur radio symposium and operating event there, called AmTech Day [k6ya.org]. Now that no morse code test is required for any level of amateur license in the US, it's a great time to get into amateur radio and experiment with digital communications, microwave technology, satellites, or even Maker [makezine.com] style operations such as bouncing radio waves off the ionosphere with equipment you can build yourself.

Bebo did mention this and actually showed us an apparatus that they use to realign the the accelerator. It's this big tube that sits beneath the actual accelerator tube and can be moved with Jacks. There is a target that a beam is shot through to make sure it is straight. Here is a photo of an intersection of the tube.
http://beta.zooomr.com/photos/thomashawk/735653 [zooomr.com]
They didn't have to realign it during the Loma Prieta earthquake though although they did lose power to the accelerator during that earthq

Well, we did have some circuit breakers fall off a shelf, too:-)The accelerator shut down during the earthquake because the PPS (Personnel Protection System) sensors were jarred. I saw someone trip it once by backing a cart into an access door. When things get really quiet you know you've screwed up.... (are you out there Roger?)

What Bebo didn't tell you about the alignment (or you didn't mention), is that they do it when the system is up to temp -- so the tunnel is very warm (like 110 to 120 F). Not a

This takes me back to when I was a NeXT Campus Consultant at Stanford-- one of my duties was the maintenance and sales of NeXT hardware at SLAC. At the time, I was also an Amiga enthusiast, and was amazed to see how entrenched the Amiga was at SLAC. Mostly due to the encouragement of Willy Langeveld, some great scientific apps came out of SLAC for the Amiga: VLT, Hippograph (both Willy's), TeX (authored by Stanford alum Tom Rokicki); I'm sure there were others. I even saw an A500 out on the floor, in production.

The biggest impression I had of SLAC in the late 80's was of gigantic, warehouse-sized rooms filled with massive, unused rusted machinery. Reminiscent of the Orrery in Oblivion, or Oghma's lair from Dark Crystal. Weird and amazing place; but perhaps my memory has augmented the tour a bit.

AmigaTeX, for its time, was arguably the finest implementation of TeX. But no, no implication meant, nor did I mean to imply that AmigaTeX's creation was tied to SLAC in any way-- its use was ubiquitous on the Amigas at SLAC, while Tom Rokicki attended to his doctorate and maintained the program while at Stanford.

Yes, we had about 100 Amigas at SLAC at one time. Most of them were Amiga 500's which were used as intelligent graphical terminals to access the linear accelerator control system. The rest were scientific workstations, mostly A2000's and later A3000's for scientists. Even the director of SLAC had an Amiga. An Amiga 3000T was used as a data acquisition system, connected to CAMAC hardware, for one of the experiments.

>SLAC is both the longest and straightest building in the world and is the home of three Nobel Prizes in physics.
Only until the next big SF quake... After which it will have to be renamed the SPLAC (Stanford Piecewise Linear ACcelerator).

You can go on a tour of SLAC pretty much every week and they are pretty interesting - especially if you know something of particle physics. Had the opportunity to take one when I was out in San Jose and thoroughly enjoyed it, and would heartily recommend it to anyone else in the area. Not surprisingly, my photos probably look very similar to the ones posted here.My Photo [chase.net.au] Tour Times [stanford.edu]